10 Weird Things You Didn’t Know Were Contagious

You wouldn't think of using your gym's elliptical without first wiping it down, and you've been giving anyone with the slightest of sniffles a wide berth since you could walk. But it turns out some of the most contagious things lurking about don't even involve germs—and all the hand sanitizer in the world won't keep these weird things at bay. Check out these surprisingly “catching” issues and the simple ways to protect yourself.

A stressful day for your office mate may rub off on you, according to research from the journal Social Neuroscience. The study shows that even simply seeing an anxious person ups your stress hormones. "To protect yourself, take steps before and after you interact with a stressed-out person," says Elizabeth Lombardo, PhD, a Chicago-based psychologist. When you have to deal with a stressed coworker, tell yourself, "I choose not to absorb her stress." Afterward take a few deep breaths to calm yourself before going back to work. (Check out Dr. Oz's top tips for fighting stress.)

If you want what you can't have, you’re in good company. A 2012 study in the Journal of Neuroscience shows that people rate an object as more desirable when they think another person wants it. "I call this wedding-band syndrome," says Lombardo. "A man is more attractive if someone already wants him—he must be worth having." Put the kibosh on desire by stopping the comparisons, says Lombardo. Remind yourself that happiness (which people tend to think they'll achieve by obtaining the desired thing) doesn't come from having what others have—no matter how pretty those shoes may be.

When you see someone scratching her head, your own scalp is probably about to get super-itchy, too. Watching someone scratch an itch produces itchy feelings in the observer, finds a study published in the journal PNAS. "People often unconsciously mimic other peoples' behaviors," says Jonathan Alpert, NYC psychotherapist and author of Be Fearless: Change Your Life in 28 Days. "Even if at a very subtle level, it's in part how we empathize and connect with people. Behaviors such as itching (and yawning) are highly suggestive behaviors and the natural tendency is to copy them."

Remember the teenage girls in Amherst, NY, who recently developed strange Tourette’s-like symptoms? You can chalk that up to mass hysteria, which typically spreads when we look for cues from others on how to behave, says Lauren Napolitano, a licensed psychologist in Bryn Mawr, PA. "If you're at a loud concert, for example, but others look like they’re enjoying it, you rationalize that you're supposed to enjoy loud music. If, in the same situation, you saw others covering their ears, you would agree it's too loud." Similarly, hysteria can become "contagious" as we can take on emotions of those around us, says Napolitano. Furthermore, new research shows we can pick up on fearfulness from others much like animals—through body chemicals.

If you use a towel at the gym that's not as clean as it should be, and then notice a rash in the shape of a ring with normal-looking skin in the center, you may have ringworm. It’s not actually a worm at all, but a fungus, says Michael Schmidt, PhD, microbiologist professor at the Medical University of South Carolina. "And you’re most likely going to catch it at the gym, as it's easily transmitted by towels or contact." It can be carried by pets as well. The good news it that most cases clear up with over-the-counter antifungal products.

An itch that drives you crazy may be a sign you've been bitten by the human itch mite, resulting in scabies. "As the name implies, it makes you itch like crazy," says Schmidt. The mite burrows deep into the upper layer of the skin, where it wreaks havoc that results in a purple pimple rash. It takes 4 to 6 weeks to develop, making it difficult to pinpoint its origin, but experts suspect it's spread from skin-to-skin contact. If you get it, be sure to wash your linens and clothes in hot water (over 122°F) with bleach before using them. Treatment involves a prescription scabicide.

Social networking as a way to connect with others may, ironically, make you feel lonelier, according to research published in the Journal of Personality and Social Psychology. "Loneliness tends to escalate because people are attempting to associate or socialize virtually with other lonely people, all of whom really need direct social contact," says David Solly, a psychology professor at University of the Rockies. "A copycat effect ensues, under which all involved tend to increase in their feelings of loneliness." The solution: Log off and get thee to a coffee shop to meet up with a friend.

Numerous studies show dining with people who overeat makes it more likely you, too, will eat too much, potentially leading to bigger weight issues. For example, a University of California, San Diego, study of more than 12,000 people found that if one person became obese, the people closest to him were 57% more likely to put on weight. "To avoid 'catching' obesity from your friends, you must be confident in your own decision to eat healthier," says Lombardo. Plus, making the choice to eat well can also be contagious, helping inspire healthier decisions from those around you.

When your friend smells another person's body odor and feels disgust, you may pick up the same feelings of repulsiveness if you're nearby, according to a study from the University of Wisconsin-Madison. Recent evidence suggests that pheromones released by a person experiencing fear or disgust affect other individuals. "Emotional contagions" were previously believed to operate solely visually or by verbally expressing disgust, but this study shows people are also able to perceive and communicate emotional states through chemical signals, similarly to animals.

On the flip side of negative emotional contagions like disgust and stress, happiness can also spread like, ahem, germs—particularly through Facebook, according to research by PLOS ONE. Researchers found that each positive post generated about 1.75 additional uplifting posts amongst friends, while each additional negative post garnered 1.29 more negative posts. "The Facebook culture promotes positivity and feel-good stories," says Lombardo. "Make the most of it by keeping posts positive with stories of resiliency, gratitude, and inspirational quotes."